Apparatus for propelling watercraft

ABSTRACT

An apparatus for use in propelling a watercraft having:
         a housing with a hollow interior and having a water inlet end and a water outlet end;   a central hub adapted to receive a propeller shaft; and   a plurality of blades radiating out of the hub;
 
the apparatus arranged such that the blades and hub are provided within the housing and the blades are fixed to the housing and to the hub, the apparatus is formed such that when in use with an engine on a watercraft, the propeller shaft of the engine is inserted into and attached to the hub and activation of the engine causes the shaft, hub, blade and housing to all rotate resulting in the apparatus propelling the watercraft across or through the water.

FIELD OF INVENTION

The invention generally relates to apparatus for propelling watercraft. More particularly but not exclusively the invention relates to watercraft propulsion apparatus which minimises damage to people and marine animals caused by contact with propeller blades.

BACKGROUND

The use of propellers on watercraft has been known for some time. A known problem of propellers is that they can pose a danger to any property or persons that come into contact with them. These propellers can also cause injury or damage to marine animals and vegetation when in use.

It is an object of a preferred form of the present invention to go at least some way towards addressing the above problem. While this is an object of a preferred embodiment, it should not be seen as a limitation on the scope of the invention as claimed. The object of the invention per se is simply to provide the public with a useful choice.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein; this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in the United States of America or in any other country.

The term “comprising” and derivatives thereof, eg “comprises”, if and when used herein in relation to a combination of features should not be taken as excluding the possibility that the combination may have further unspecified features. For example, a statement that an arrangement “comprises” certain parts does not mean that it cannot also, optionally, have additional parts.

SUMMARY OF THE INVENTION

According to one aspect of the invention there is provided an apparatus for use in propelling a watercraft having:

-   -   a housing with a hollow interior and having a water inlet end         and a water outlet end;     -   a central hub adapted to receive a propeller shaft; and     -   a plurality of blades radiating out of the hub;         the apparatus arranged such that the blades and hub are provided         within the housing and the blades are fixed to the housing and         to the hub, the apparatus is formed such that when in use with         an engine on a watercraft, the propeller shaft of the engine is         inserted into and attached to the hub and activation of the         engine causes the shaft, hub, blade and housing to all rotate         resulting in the apparatus propelling the watercraft across or         through the water.

Preferably the blades are welded to the inside of the housing.

Preferably the blades are welded to the outside of the hub.

Preferably the blades are fastened with screws to the housing.

Preferably the central hub has an outer hub and an inner hub.

Preferably the outer hub and inner hub are connected by ribs.

Preferably there are three ribs.

Preferably the hub has an internal female spline adapted to receive a male spline on a propeller shaft.

Preferably the apparatus has at least three blades.

Preferably the apparatus has at least four blades.

Preferably the housing is substantially cylindrical.

Preferably the apparatus has at least one bracket which is welded to at least one blade and the bracket is fastened to the housing with screws.

Preferably the apparatus has a tapered cone which is adapted to releasably engage with the water outlet end of the housing.

Preferably the cone is adapted such that it can releasably engage with a propeller shaft.

Preferably the housing, blades and hub are made substantially from plastic, fibreglass and/or carbon fibre.

Preferably the housing, blades and hub are made substantially from aluminium and/or stainless steel.

In another aspect of the invention there is provided the previously described apparatus when in use with a watercraft.

In a further aspect of the invention there is provided the apparatus when in use with an outboard engine.

In another aspect of the invention there is provided the previously described apparatus when in use with an inboard engine.

These and other features, objects and advantages of the present invention will be readily apparent to persons of ordinary skill in the art upon reading the entirety of this disclosure, which includes the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Some preferred embodiments of the invention will now be described by way of example and with reference to the accompanying photos, of which:

FIG. 1 is a front view of an apparatus for propelling watercraft;

FIG. 2 is a rear view of the apparatus; and

FIG. 3 is a side view of the apparatus.

DETAILED DESCRIPTION

FIG. 1 shows an apparatus for propelling a watercraft 1. References throughout the specification to a watercraft relates to any ship, boat or vessel that travels on water. The apparatus 1 has an outer housing 2 which is preferably made from plastic, fibreglass or carbon fibre but can also be made from any other suitable materials such as stainless steel or aluminium etc. As shown the housing 2 has a hollow interior and is open at both the front and at the rear allowing water to pass through it when in use. The housing 2 is cylindrical in shape however it will be appreciated by those skilled in the art that the housing 2 can come in different shapes and sizes.

As shown the apparatus 1 has four blades 3 the outer edges of which are welded to the inside of the housing 2. The blades 3 are also welded to a hub 4 however it will be appreciated that the blades 3 can be fixed to the housing 2 and/or hub 4 by other means and in some embodiments the blades 3 can be cast as part of the hub 4 during the manufacturing process. The blades 3 shown are made from metal such as stainless steel however it will be appreciated that the blades 3 can be made from any suitable material. Those skilled in the art will appreciated that the number of blades 3 can vary as can the size and shape of the blades 3. As the blades 3 are enclosed within the housing 2 this helps reduce blade strike on users and on marine animals when in use. The housing 2 also helps to prevent damage to property and marine vegetation caused by contact with the blades 3, and also prevents damage to the blades 3 themselves.

The hub 4 which is the attachment point for the blades 3 and for a propeller shaft (i.e. a drive shaft/gearbox output shaft) from an engine has an outer hub 5 and an inner hub 6 which are connected together by three ribs 7 which create exhaust passages. It will be appreciated that the number of ribs 7 can vary as can the size and shape of them. The hub 4 is rotatable about a rotation axis and at the center of the inner hub 6 is a female spline 8 which receives a male spline on a propeller shaft (not shown) when in use. It will be appreciated by those skilled in the art that the number and shape of the teeth on the spline 8 can vary so that the apparatus 1 can be used on different engine models.

As can be seen in FIGS. 2 and 3 certain parts of the blades 3 are welded to a bracket 9 which is substantially perpendicular to the blade 3 which results in an L-shape in places. The bracket 9 is fastened to the housing 2 by way of screws 10 or the like. As shown the bracket 9 only goes along half the length of the blade 3 although it will be appreciated by those skilled in the art that the length, shape and size of the bracket 9 can vary. In some embodiments the bracket 9 can form part of the blade 3.

In some embodiments the apparatus 1 has a tapered cone (not shown) which attaches to the rear of the apparatus 1 and is also adapted to receive the same male drive spline from the propeller shaft as the apparatus 1 and is attached to this when in use. The cone reduces the diameter of flow through of fluid giving high volume/high pressure resulting in extra thrust.

The apparatus 1 can be mounted to various types of inboard and outboard engines and a user can replace their existing engine propeller with the apparatus 1.

In use a propeller shaft of an engine (not shown) of a watercraft is fitted into the centre of the inner hub 6 and the female spline 8 receives the male spline on a propeller shaft. The shaft is then secured to the hub 4 for example with a thrust washer, spacer, washer and nut etc. Once the apparatus 1 is placed in a body of water and the engine is activated the engine causes the shaft, hub 4, blades 3, and housing 2 to all rotate as they are all fixed together with the result that the apparatus 1 propels the watercraft across or through the water.

As the blades 3, housing 2 and hub 4 all revolve as one this pulls in fluid in high volume, low pressure and converts it into high volume, high pressure creating thrust.

It will be appreciated that the various parts of the apparatus 1 can be made in a number of different ways for example one or all of the parts can be made by plastic injection moulding, hand-layered in fibreglass or carbon or cast in stainless steel or aluminium.

Apart from the safety benefits previously mentioned the apparatus also has a number of additional benefits/advantages such as elimination of aeration of blade surface as known propeller apparatus have elements of blade aeration. The apparatus also eliminates prop steer. Known propeller apparatus have prop steer issues unless fitted with some form of stability system. As the blades are fixed to the housing and hub the apparatus is able to be manufactured from eco-friendly materials such as fibreglass, plastic or carbon fibre which makes the apparatus lightweight. The design of the apparatus also enhances fuel efficiencies compared to existing propeller systems which results in cost efficiencies. The apparatus also has enhanced performance and has smooth running characteristics compared to known propeller systems.

It is to be understood that even though numerous characteristics and advantages of the various embodiments of the present invention have been set forth in the foregoing description, together with details of the structure and functioning of various embodiments of the invention, this disclosure is illustrative only, and changes may be made in detail so long as the functioning of the invention is not adversely affected. For example the particular elements of the housing, blades and hub may vary dependent on the particular application for which it is used without variation in the spirit and scope of the present invention.

In addition, although the preferred embodiments described herein are directed to an apparatus for propelling a water craft, it will be appreciated by those skilled in the art that variations and modifications are possible within the scope of the appended claims. 

1. An apparatus for use in propelling a watercraft having: a housing with a hollow interior and having a water inlet end and a water outlet end; a central hub adapted to receive a propeller shaft; and a plurality of blades radiating out of the hub; the apparatus arranged such that the blades and hub are provided within the housing and the blades are fixed to the housing and to the hub, the apparatus is formed such that when in use with an engine on a watercraft, the propeller shaft of the engine is inserted into and attached to the hub and activation of the engine causes the shaft, hub, blade and housing to all rotate resulting in the apparatus propelling the watercraft across or through the water.
 2. An apparatus according to claim 1, wherein the blades are welded to the inside of the housing.
 3. An apparatus according to claim 1, wherein the blades are welded to the outside of the hub.
 4. An apparatus according to claim 1, wherein the blades are fastened with screws to the housing.
 5. An apparatus according to claim 1, wherein the central hub has an outer hub and an inner hub.
 6. An apparatus according to claim 1, wherein the central hub has an outer hub and an inner hub and wherein the outer hub and inner hub are connected by ribs.
 7. An apparatus according to claim 1, wherein the central hub has an outer hub and an inner hub and wherein the outer hub and inner hub are connected by three ribs.
 8. An apparatus according to claim 1, wherein the hub has an internal female spline adapted to receive a male spline on a propeller shaft.
 9. An apparatus according to claim 1, wherein the apparatus has at least three blades.
 10. An apparatus according to claim 1, wherein the apparatus has at least four blades.
 11. An apparatus according to claim 1, wherein the housing is substantially cylindrical.
 12. An apparatus according to claim 1, wherein the apparatus has at least one bracket which is welded to at least one blade and the bracket is fastened to the housing with screws.
 13. An apparatus according to claim 1, wherein the apparatus has a tapered cone which is adapted to releasably engage with the water outlet end of the housing.
 14. An apparatus according to claim 1, wherein the apparatus has a tapered cone which is adapted to releasably engage with the water outlet end of the housing and wherein the cone is adapted such that it can releasably engage with a propeller shaft.
 15. An apparatus according to claim 1, wherein the housing, blades and hub are made substantially from plastic, fibreglass and/or carbon fibre.
 16. An apparatus according to claim 1, wherein the housing blades and hub are made substantially from aluminium and/or stainless steel.
 17. An apparatus according to claim 1, when in use with a watercraft.
 18. An apparatus according to claim 1, when in use with an outboard engine.
 19. An apparatus according to claim 1, when in use with an inboard engine. 